Ever had a lemon? Or anything sour? Then you have eaten an acid. Acids can be harmful like battery acid, but most acids are safe to eat like lemons, limes, and vinegar. In this activity students will explore how the properties of acids can be used to help clean objects. When acids are mixed with other compounds like salt, they form special molecules called ions. These ions are able to react with other compound nearby and have chemical reactions that can be used to change other substances, or in this case, clean the penny.
In this experiment students will experiment with the properties of an acid.
Measuring cup (1/2 cup)
Pennies (dirty and old pennies work best)
Lemon Juice and salt
- In a small bowl, mix ½ cup of lemon juice with a tablespoon of salt.
- Take a small amount of taco sauce and begin rubbing the pennies with it. (Use your hands, the more you scrub the better!)
- Periodically dip the penny in the lemon juice and salt mixture to help clean the penny even more.
- Scrub the penny for about 5-10 minutes until the pennies are nice and shiny.
How It Works: The taco sauce has vinegar and salt in it, which when combined form a super cleaning mixture. When salt is dissolved in vinegar it breaks into two ions (or charged particles), sodium and chloride. These ions are able to then mix with the copper oxide (a.k.a. rust) on the penny and dissolve the rust, leaving the penny shiny like new. The lemon juice and salt mixture does the same, with the salt dissolving in the lemon juice to form the cleaning machines, sodium and chloride.
When teaching Chemistry concepts, it is best to do hands-on activities. There are great vocabulary words that can be reinforced during Chemistry-related activities, like liquid, solid, acid, base, even words like chemical change, and physical change. There are lots of Chemistry topics around us everyday from how we cook foods to how our bodies breakdown the food we eat. For more useful teaching techniques related to acids and to everyday chemistry, you can visit: http://www.watchknowlearn.org/SearchResults.aspx?SearchText=acids or
And for other Fun Learning Science Games, we invite you to visit here: